In agricultural applications, remote image sensing is the technology of choice for gathering timely, frequent, and cost efficient information about soil and crop status. However, remote image acquisition systems such as the new generation of high-resolution satellite and aircraft imaging systems must be calibrated, for example with respect to reflectance or thermal radiance. Imaging sensors such as scanners, cameras, or line arrays are used in these image acquisition systems to image target fields from elevated positions. The imaging data is typically digitized for later analysis. Calibration of remote or downward viewing image acquisition systems permits the application of quantitative models to the remotely sensed images and makes the data comparable between spatially separated fields and through time in order to extract useful information from the images. Without calibration, the information from remotely sensed images is typically limited to showing relative changes or anomalies concerning the imaged field. Currently, the only available calibration target on the market consists of a set of six cloth-backed panels from TRACOR which costs $60,000. These panels are difficult to handle, require intensive effort to lay out in a field, are easily damaged, and cannot remain in the field, but instead must be gathered up after the calibration exposure is completed. Deployment requires significant labor costs when sites are remote or when images must be acquired frequently.
Accordingly, there is a need in the art of remote image acquisition technology to provide inexpensive, portable, and robust calibration targets which are easily deployable in or near fields to be imaged and provide optical and thermal imagery characteristics for calibrating remote or downward viewing image acquisition systems used in agricultural and other applications. Currently, no such product is available.